[gdal-dev] Problem creating geo-tiff from scratch

[Chaitanya kumar CH]

Marco,

1. You misspelled the option for world file creation as 'TWF' which should
actually be 'TFW'.
2. The driver did report the error message correctly after processing the
creation options. There may be a bug with the debugger.


On Tue, Jul 6, 2010 at 6:26 AM, Marco Zuliani <zuliani at mayachitra.com>wrote:

> Dear all,
>
>  I am trying to utilize GDAL to generate a geo-tiff image from scratch. I
> have been following the tutorial presented at
> http://www.gdal.org/gdal_tutorial.html and I have been reading the
> documentation of the functions involved in the process, but so far I have
> not beed successfull in accomplishing my goal.
>
>  In the following I will first paste (partially) my routine in the fervent
> hope that somebidy can spot my error and help me out. I will denote with
> [...] portions of the code that have been omitted because I believe they are
> not relevant to my question. After the listing I will present my questions.
>
>  --- CODE BEGINS ---
>
> [...]
>
>     // There is a driver for each supported format. Attempt to register all
> known drivers
>     // Ensure that GDALAllRegister() has been called before calling
> GetDriverByName().
>     GDALAllRegister();
>
>     // select the geotiff format for GDAL
>     const char *pszFormat = "GTiff";
>     GDALDriver *poDriver = GetGDALDriverManager()->GetDriverByName(
> pszFormat );
>
>     // make some checks to avoid headaches in the future
>     if ( poDriver == NULL )
>     {
> // take care of the error condition
>  [...]
>     }
>
>      // get some info regarding the GDAL driver
>     char **papszMetadata = poDriver->GetMetadata();
>
>     if ( !CSLFetchBoolean( papszMetadata, GDAL_DCAP_CREATE, FALSE ) )
>     {
>  // take care of the error condition in case creation is not possible
>     }
>
> [...]
>  // at this point the some variables used in a while have the following
> values
>  // width = 251
>  // height = 234
>  // bands = 4
>      // this hosts the list of driver specific control parameters.
>     // See http://www.gdal.org/frmt_gtiff.html
>     char **papszOptions = NULL;
>     papszOptions = CSLSetNameValue( papszOptions, "TWF", "NO" );
>     papszOptions = CSLSetNameValue( papszOptions, "TILED", "NO" );
>
>     int height  = FreeImage_GetHeight( I );
>     int width   = FreeImage_GetWidth( I );
>     // this is the georeferenced image
>     const char *options = GDALGetDriverCreationOptionList(poDriver);
>     GDALDataset *Ig = poDriver->Create( "test.tif", width, height, bands,
> GDT_Byte, papszOptions );
>  --- CODE ENDS ---
>
> Questions:
>
> 1] The program outputs to the console the following message: "Warning 6:
> Driver GTiff does not support TWF creation option". Why? From the
> documentation at http://www.gdal.org/frmt_gtiff.html it seems that such
> option is supported...
>
> 2] From Visual Studio debugger I can see that the values of poDriver are
> messed up and also the values of eAccess, nRasterXSize, nRasterYSize, nBands
> seem to be scrabled (I would expect nBands = 4, nRasterXsize = 251, etc.).
> Does anybody have an idea of what's going on? (Please find below the output
> of the debugger Name/Value/Type)
>
> - Ig 0x00000000039fa450 {hTIFF=0x00000000039fa000
> ppoActiveDSRef=0x00000000039fa560 poActiveDS=0x00000000039fa450 ...} GDALDataset
> *
> + [GTiffDataset] {hTIFF=0x00000000039fa000
> ppoActiveDSRef=0x00000000039fa560 poActiveDS=0x00000000039fa450 ...}
> GTiffDataset
> + GDALMajorObject {nFlags=33 sDescription={...} oMDMD={...} }
> GDALMajorObject
> - poDriver 0x000000fb00000001 {pfnOpen=??? pfnCreate=??? pfnDelete=???
> ...} GDALDriver *
> + GDALMajorObject {nFlags=??? sDescription={...} oMDMD={...} }
> GDALMajorObject
>  pfnOpen CXX0030: Error: expression cannot be evaluated
>  pfnCreate CXX0030: Error: expression cannot be evaluated
>  pfnDelete CXX0030: Error: expression cannot be evaluated
>  pfnCreateCopy CXX0030: Error: expression cannot be evaluated
>  pDriverData CXX0030: Error: expression cannot be evaluated
>  pfnUnloadDriver CXX0030: Error: expression cannot be evaluated
>  pfnIdentify CXX0030: Error: expression cannot be evaluated
>  pfnRename CXX0030: Error: expression cannot be evaluated
>  pfnCopyFiles CXX0030: Error: expression cannot be evaluated
>  eAccess 234 GDALAccess
>  nRasterXSize 4 int
>  nRasterYSize 60761968 int
>  nBands 0 int
> + papoBands 0x0000000100000000 GDALRasterBand * *
>  bForceCachedIO 0 int
>  nRefCount -1163005939 int
>  bShared 0 int
> + oOvManager {poDS=0x0000000000000000 poODS=0xbaadf00dbaadf00d
> osOvrFilename={...} ...} GDALDefaultOverviews
>
> Thanks in advance for your help,
> Marco
>
> Marco Zuliani, Phd
>
> phone: +1 805 967 9828
> web: www.mayachitra.com
>
> _______________________________________________
> gdal-dev mailing list
> gdal-dev at lists.osgeo.org
> http://lists.osgeo.org/mailman/listinfo/gdal-dev
>



-- 
Best regards,
Chaitanya kumar CH.
/tʃaɪθənjə/ /kʊmɑr/
+91-9494447584
17.2416N 80.1426E
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